1. Field of the Invention
The present invention relates to an image data forming method and apparatus, and in particular to an image data forming method and apparatus utilizing a CCD imaging element having a binning mode.
2. Description of the Related Art
There are known a variety of methods wherein: image data that has been obtained by a use of a CCD element is temporarily separated into high- and low-frequency image components; each component is subjected to image processes to enhance the outline of the image component, to smooth the image component and the like; then, the image components are again synthesized to form a synthesized image data appropriate to the desired use, such as observation or the like, to which the image is to be put.
In the field of biochemical analysis, for example, there are known protein analysis apparatuses that cause cataphoresis in proteins that have been processed, utilizing markers such as fluorescent pigments and the like, to create samples formed of cataphoresis patterns formed of bands constituted by a plurality of protein molecules aligned in a band oriented in the direction of an electrode. By irradiating these samples with an excitation light, the faint fluorescence emitted thereupon is obtained as image data, based upon which the aforementioned synthesized image data is formed and the protein analysis conducted.
The CCD imaging element employed in apparatuses such as those described above must be high resolution and high S/N ratio imaging elements in order to accurately detect the emission intensity data (concentration data), the position data of each band, and the like, of the faint fluorescence emitted from each cataphoresis band upon the irradiation thereof by the excitation light.
Further, regarding specific methods of forming synthesized image data that accurately represent the concentration data, position data and the like of each band, methods are known, for example, wherein: an obtained image data is separated into high frequency image data representing mainly the high frequency component and low frequency image data representing mainly the low frequency component; the high frequency image data is subjected to an edge enhancement process to render the outline of each band clear; the low frequency image data is subjected to a smoothing process to reduce the noise component, which is present primarily in the high frequency end of each band so as to render the concentration datamore precise; then, the two processed image data are synthesized to form a synthesized image data accurately representing the concentration and outline (position of each band) of each band.
However, because the fluorescence emitted from the sample and which represents the cataphoresis pattern is extremely faint, even if the low frequency image data is subjected to a smoothing process or the like and the noise on the comparatively high frequency side is reduced and the synthesized image data formed, there are cases in which it is impossible to discriminate between bands having respective different emission intensities (concentrations). The concentration of each band cannot be discriminated due to the fact that a portion of the concentration image data of each band of the image data obtained of the extremely faint fluorescence emission becomes buried in the noise included in the comparatively high frequency side of the low frequency image data; to prevent the concentration data from becoming buried in the noise, it is necessary to further raise the S/N ratio of the CCD imaging element.
Although the S/N ratio of the CCD imaging element can be raised by increasing the size of the area per pixel (e.g., by binning), generally speaking, if the size of the area per pixel is increased or the binning number made large, because the actual number of pixels of the CCD imaging element is reduced, the high frequency component of the image data suffers losses; that is to say, because the relation between the S/N ratio and resolution is one of trade-off, there is a problem in that it is difficult to improve the S/N ratio (reducing the quantity of noise of the low frequency side without causing losses on the high frequency side) without causing a deterioration in the resolution.